There are a variety of know processes for constructing building boards. One known method employs a forming line consisting of one or more forming tables. The building board, which may be a gypsum based building board, is sequentially assembled over the forming tables. A roll of a facing material, such as paper or a fibrous bounds mat, is unwound over the first forming table to form the lower surface of the board. The forming tables may include rotatable belts to transport the facing material. An overhead mixer is included for depositing a volume of cementitious slurry upon the inner surface of the facing material. An additional roll is included for providing an opposing facing material.
These known methods suffer from several disadvantages. For example, the friction between the facing material and the forming table often damages or mars the resulting budding board. This may result in the board being unsuitable for its intended use. Furthermore, known manufacturing techniques often result in an uneven distribution of cementitious slurry during formation. Most often the slurry disproportionally accumulates along the center line of the board, closest to the outlet of the overhead mixer. As a result, the edges of the resulting board are insufficiently strong and are prone to chipping or disintegration.
Over the years, various devices have been created for improving the board manufacturing process. For example, U.S. Pat. No. 2,722,262 to Eaton discloses an apparatus for the continuous production of a paper encased gypsum plaster strip. The apparatus includes a table over which a continuous strip is passed. The apparatus further includes a block and side guide members for shaping the strip and associated gypsum.
U.S. Pat. No. 3,529,357 to Hune et al. discloses method and apparatus for the high-speed drying of gypsum boards. The apparatus includes jet nozzles that impinge heated air on the this edge portions of the materials throughout a drying process.
Yet another manufacturing method is disclosed by U.S. Pat. No. 5,342,566 to Schafer et al. Schafer discloses a method and apparatus using air jets to support a gypsum board prior to cutting. The air cushion provides a lifting force but does not impart any forward motion.
U.S. Pat. No. 4,298,413 to Teare discloses method for producing fabric-reinforced thin concrete panels that are suitable as backer board for construction materials. Constructed panels can be transferred in seriatim to an air-float stacking unit positioned over a stacking table.
Finally, U.S. RE 41,592 to Lynn et al. discloses a manufacturing method for producing gypsum/fiber board with improved impact resistance. The method utilizes airjets to support the gypsum fiber board during processing.
Although the aforementioned methods each achieve their own unique objectives, all suffer from common drawbacks. The devices and methods described herein are designed to overcome the shortcomings present in background art. In particular, the devices and methods described herein employ pressurized air for the purpose of transporting building boards, ensuring adequate slurry spread, and/or preventing the boards from being damaged or marred during manufacture.